Process of destroying insect life



F. S. SMITH.

PRocEss of ussmovmsmmsec UFE. l APPLICATION FILED APR. 30, 191.8. v1,352,699.

RENEWED OCT. 2l, 19I9.

INVENTOR A TTUHNEV PROCESS 0F.D

APPucATloN HLEp APR.

llllllllllllllllllll IIIINHHIIII llllllllllll Il UNITED' vST'.f1-'11u55 PTEQNPOFSICE! 'FRANKLIN'-S. satira; N oF' PHILADELPIA; PENNsYLvANiA.

,Specification of Letters Phatentf- Paftntd'spt.

Appiicatm mea Aprileo, 191s, seri/a1 No. 231,666. Renewed otober 21', '1919. serino'g $323111.

To all who'dm A z'z mag/concern: l-

Be it known that I, FRANKLIN S.- SMITH,

a citizen of the United States, residing in the, city ofPhiladelphia, State of Pennsyljvania, have invented a certain new and use-` ful Process of- Destroying Insect Life, of!

which the following is' a specification.

My invention relates to the art of destroying insect life infested food and' otherturing or otherwise.

products without injury' to the product1V 'Myl invention said onsist.

broadly'in the subjection ofthe product in fested with' insect 'life-to the action of electrical'disruptive conduction, ofa current 6 0 retreated, and of properly controlled voltage gradients. l, l The treatx'ne'entishould bepractically h-omo- 65 gencous; that is, every part of the product l? treated. By the words insect life7 emor article treated should be subjected as far ployed herein, I intend to include not only as is practicably' possible to' *al like action ofv the; insect or imago itself, but also the' egg, the current. i Y. l, larva-and pu a. e As has already been indicated, the voltage 70 'IZVithout attempting. to enumerate all of; gradients must be less thanthe rupturnf'g the products which may be treated according gradients of the products or V'articles being to my invention, I may mention grain`s,. treated'or the container for the same, in case bean s,'milled cereals, dried ruits,etc.; also such' product or article-'should be inclosedf l furS, woolens, et'c. It is to be understood '/\wii;hin a Container;- algO- ther Current density 75.

however,`that the employment or use of my must be. less than that which would cause vinvention is not limted"or confined to the damage to the product or'article by carbon- Y treatment f the products designated above, Aization,dehydration, etc.

but may beemployed or used' for the treat; The objects ofmy invention generally may ment,of cmany` other products for the de l be stated to be to provide aprocess orthe 80 '25 struction of insect life which may infest the treatment of products and articles infested same. Y with insect lifebymeans of electrical disw 4In order to bepractically 'and commerruptive conduction and, to so control and cially successful, it is necessary that an art Vregulate the density oiv the current as to or method designed for the treatment of prevent carbonization, dehydration, etc., of 85 Aproducts as indicated above andrfor the the product or article being treated, also to purpose stated, shall not only be capablel ofi so control -and regulate the voltage gradlents4 .being used forl the treatment of products as t0 limit the same to values less than the .when they are not inclosed in receptacles rupturing gradients of' the product' or arsuch as the 'usual Commercial pasteboalfd ticle being/treated or the container for the 90 3 cartons. but also when they are so inclQSed. same, if it be inclosed within a container.

' I have-found by actual,pract1cal experience ls The process nvened by-meis not dependthat my invention is Vadmirably suited-fol' 'fent upon anyparticularlform of apparatus theA treatment 0f PI'QdllCtS 100th When lfor its commercial and practical utilization, ClOSedtaIld When IlIIlZDClOS'edin IBCeptLClQS." although apparatus 0f Some kind is essential- 95 40 IV have ascertained by actual "experience and to its' utilization .andin the aeggmBanying practice that the -pr0CeSS embOdylIlg my m- 'drawings I have lllustrated schematically a VeIltOD may be' employed in vthe treatment? novel and veryeiicient construction of apof food productsl such as cereals, milled A011 paratus which I propose to employ for the unmilled,'in pasteboard cartons,'withpout any vtreatment of products and articles for the 100- injury whatever to such cartons. v1s necespurposes herelnbefore set forth and indisary, in the treatment of productsln cartons, cated. s that the pasteboa'rd. of whlchthedlatter are e In the drawmgs accompanylng lthis apconstructed shall' not' bev punctured by the plication:

electrical discharge" caused tol pass through Figure l is a view showlng an apparatus 105 the package. It is one of the lnovel features Fadapted for the practising of my p rocess of'my invention that products contained in partly in sectlon and partlyin elevation; pasteboard cartons may 'be' subjected -to i F1g. 2 1s a topplan'vieyv of a portion of a treatment and all of the insect life which the apparatus shown in'Fig.v 1,; and may be present therein 'destroyed without, F1g .3 1s a'sectlonal view showing adetail 1.10 in the slightest, injuring the carton by puncuof construction.

Iteferring fto' the drawing-s;` 1 designates relation with respect to each other.

plates are rounded at their outer edges so as to prevent too great a flux concentration y at such edges. These condenser plates are respectively situated in receptacles or containers 10 and 11, consisting of dielectric material, such, for instance, as bakelized liber. These containers contain and .are lilled preferably with a liquid dielectric'12 such as transformer oil, paraflin oil, etc. The liquid dielectric is introduced into the containers 10 and 11 through pipes 13 which may be closed by Stoppers o-r in any other suitable way. It is obvious that a solid dielectric could be used, preferably a waX, such vas ceresin. Coperating with the respective condenser plates 6 and 7 are a plurality of small condenser plates 15 and 16. These condenser plates are situated within andare supported upon the opposing ad-v jacent sides of the containers or receptaclesA 10 and 11. Inorder to prevent possible leakage between the small condenser plates of the respective groups thereof, thefsaid plates are each provided with a small central projection as indicated at 17 in Fig. 3, which supports'theHgreater-portions of the underneath surfaces of the said plates in spaced relation to thev portions of the containers l10 and 11 upon which they are supported. i

The liquid 12 within the containers 10` and 11 occupies the spaces between the condenser plates 6 and 7 and the respective groups of small condenser plates. 15 and 16 and constitutes the dielectricvbetweenthe saidJ condenser plates 6 and 7 andthe respective groups of small condenser plates 15 and 16 and between the small condenser plates themselves.

vEachof the small condenser plates 15 and V16 is connected by means of a shankor rod 18, which extends through the adjacent opposing sides of the containers 10 and 11, with a spa-rk gap electrode 20, the lsaid electrodes being situated in opposing'relation with respect to each other'as is shown in Fig. 1 of the drawings. f

In the apparatus as designed and illustrated b Ine, it will be noted that lI have provide two sets `of condensers or capaci,

ties, each set comprising or including a plurality. of condenser plates in multipl'ewhichare connected each to a side of the secondary of the transformer 1 and alsothat the two sets fd lcondensers or capacities are qcon- These nected in series 'by means of the spark gap formed bythe opposing electrodes 20 having connection respectively with the plurality of small condenser plates as hereinbefore described. It will be obvious to those skilled in the art that the desired result may be obtained by the employment of only one set of condensers or capacities. The means in the circuit which provides electric capacity distributes thefpotential'l drop and 'limits the current density so that the latter may be controlled and maintained at values below v the voltage gradients of the materials or obL jects being treatedf In order to convey the products or articles to be treated through thespace between the opposing electrodes, 1 have provided means consisting of a conveyer belt 25 of dielectric material, supported upon revolving drums or pulleys 26 of well known form and construction, driven in any, suitable manner from an shown. hat other means of causing'tlie product to pass between the electrodes may be employed such as gravity feed, etc., is obvious. j

Upon reference to Fig. 2 of the drawings in which the top spanning portion of the belt is shown and in which the lower container 11 and the lower group of electrodes 2() carried thereby are shown in top plan view, it will be observed that the arrange- `ment is such that-the conveyer belt extends diagonally over or angularly with respect to the group of electrodes 20. .One purpose of this arrangement is to cause the pro-ducts 0r articles being vtreated to travel diagonally across the rectangular shaped group of electrodes so that every particle of and point within the product or. article will be subjected to the current discharged across the space between the electrodes 20,-thereby obtaining and insuring an approximately or substantially homogeneous treatment of the product or article as it travels between the electrodes. j Y y Y In the apparatus as illustrated there are five rows of 'electrodes and thirty electrodes in each row. Let us assume that these electrodes' are one and one-half inches apart in each horizontal direction and that'the apparatus is`I connected with an' `alternating supply current of sixty cycles. ySuch al cur rent will produce or cause one hundred `and twenty group discharges per second across the spark gap between theelectrodes 20.

The conveyer belt 25 as has been already stated conveys the products or articles to be treated lat an angle to lor diagonally with respect to the4 rowsrof electrodes as is shown in- Fig-2.l The number of electrodes between which each inch transversely of the product or article being treated passes may be ascertained by dividing the number (30) of' electrodes in eachl row by the Vdistance,l

suitable source. of power, not

1% inches, between the electrodes, whicli,un der thejassumption, will give 20 as the nuin\ ber vof electrodes betweenfwhicheach transverse inch of -theproduct or 'article will,v pass; vwhich, in operation, amounts to twenty group discharges per transverse' inch' through the product or article. To ascer- ,tain the speed at which thebelt shall travell in order to secure the number of discharges desired through the product or article being treated (400 per square inch), the number, 120, of group dischargesi should be di-` vided by the number (20) of discharges per transverse in ch of the vproduct or article bef ing treated,which gives 6, the'iatter being the number of inches per second traveled by the-product orfarti'cley under the conditions stated.

It is ndt necessary that thefspeed of travel of the belt and rconsequently of the products. and larticles carried thereby to be treated shall be mathematically correct or in eXactaccordance with the figures as above indicated, but preferably in practice the travel of the belt should be somewhatl slower than it -is indicated mathematically. 'Ihe distance apart of" the discharges through thefproduct, or article being treated, or in other words the number of the dis- 30 c hargesrequired through any un-t of area lof the lproducts or 'articles being treated varies with the material. In general, the distance apart of the discharges through.

' various products varies #from one-ftieth to To insure 'homogeneous' treatment and for obviousreasons /of eiiciency, the spark gap l should .be'asshort as is practicable, that is,

just sufficient clearace-'to permit of the passage of the conveyerbeltf and the product carried thereby bet'weenthe oppos? ing electrodes 20. j I The :electrodes QOpreerably-'should consist of spheres and their radifshouldbe about one-third of, the spark gap length. After considerable use the electrode mate# rial -disintegrates leaving the surface rough. Obviously the larger the sphere the less the roughness will alter the sparkfgradient at the. surface' ofthe electrodes.v

The electrodes 'of 'each group, electrodes of the same side,- 'positiveon nega# tive, should be separatedfrom each other a' distance equal'to. aboutl one-third ofthe'l length of the spark--gapin' order to avoid .discharges betweenthe same. l The condensers preferably sho Jbe of such capacity that aboutv '1 5 wa tts.per inch of spark gap length is expendedfor milled eo cereals and about 40. vwatts:'for certain cereals, as for example rice.- The -larger the particles of the product bein'g treated the greater' amount of. energy 'is required to-- effec't eiiicient treatment.

il The hvoltage gradient acrosthe-spark g between' the electrodes 20 breaks down so that within such'carton'; The apparatus` as de- .that -1s, 'a

3c 65 should be a few kilo-volts infexcessof threi actual lvoltage required to break down, or Aru ture, the air; .t bviously the condenser dielectric strengthv must be high enough to lprevent corona or rupture, otherw be Jdamaged'. f In designigapparatus for use in the. practising of tmy invention the designer must 4havein mind the product to be treated and must provide condenser dielectrics of such dimensions and of such dielectric co n. stant that the product or its container, if there be a container, not-overstressed. In designing apparatus for carrying out my process it must be kept in mind that isc the treated product will .generally in the treatment of -cereals in .pasteboard boxes or cartons the amountof energy which may be elnployedin'unity discharge is limited bythe box or carton.

v.There are, however, certain exceptions, for

lexample -rolled oats. In granular cereals 'il `the discharge tends to take a path around the-granules whereas in the-case of certain f otherv products# for example, rolled oats,l 9 the discharge tends to 1pu'ncture the same.,

In general the smaller the particlesbeing/ -treated the less the energy whichmay be employed in unit7 discharge. For eXample v buckwheat flour would be carbonized by a l9 5 discharge which would. not harm corn meal; and the l/atter would be carbo'nized by a discharge which would not -harln 2rice.A

- The operation of myifnvention may be described as follows: The voltage ofthe secondary coil of the transformer 1 is app ied aacross the apparatus, Athat is, through the sets of condensers ,or capacities as hereinbefore described. Wherrthe voltage reaches the disruptixge Avalue the air in the spark gap currenteXists. .Uponthe breaking down of; the air, it vbecomes conducting so that most '.of the aia-#lied voltage is placed on the die# lectrics o the Y. condensers with a proporf' tional part on the conveyer belt and onthe pasteboard carton, assuming that the prod' -ucto'r article'being treated is inclosed signed`and1as above: described is lso c'onstructed and operated that the voltage gradient acrossfth'econdenser dielectrics is' 'below their rupturing value, so`-that theyl ldo not break down, in. consequence of which neither does the carton or belt because the voltage gradients 'across l`them are lbelow their rupturing gradients. A When an alternating'currentA is used, the voltaI e varies from 'zero toits highest point andt e lreverse and theoper'ationofthe apf paratus and-the process is the same for; the: successive alternations of the current.-

It *will be. under stood fthat high tension unidirectional or oscillating current also may be employed in the practising or carry# ing out of my invention and that I am not limited to the use of an alternating current such as is hereinbefore described.l

I claim: f

l. The processof treating products for the purpose of destroying insect life which consists in the subjection of the products. to the action of disruptive conduction of current density limitedto a value below that which would damage the products and ,in which the voltage gradients across 'the products are less'than lthe rupturing gradients ofthe products.

2.V The process of treating products within containers' for-.the purpose of destroying insect life, which consists'in the subjection of the products within "such containers to the action of disruptive conduction of cur- 4rent density limited to a value below that lthe :voltage gradients of the material of which the cartons are composedf and sub# jecting the cartons 'and the material therein to said discharge.

7. The process'` of -treating productsv for the purpose of destroying insect life therein, which consists in creating an' electricalJ discharge across a gap, interposing electrical h secondary coil of a transformer, discharginga disruptive conductive current across said articles and controlling the voltage gradient which would damage the products or conad lcurrent density of the said current across tainers and in which the voltage gradients across the products and containers are less than the rupturing gradients of the'products and containers being treated.

3. The process of treating products and articles withincontainers infested with insect life to destroy the latter, which consists in subjecting the vsaid products or articles to the action of electrical disruptive conduction of a current density suflicient to de\` stroy the same, and in which the available electrical energy across the products or articles. within containers values less l'than those which would cause damage to the products or articles'or their would damage the said products, and in which the voltage gradients across the products are less than the rupturing gradients of the\products.being treated, and moving' the said products across the line along which the said disruptive conduction takes place.

5. The process44 of treating products elec# ytrically, which lconsists in creating -an electrical vdischarge across a gap, interposing electrical capacity in series with said gap to ldistribute thel potential drop and limit the current `density below the voltage gradients of the material to be treated,` and` subjecting the products ,to be treated to said discharge.

6. The process of treating products contained in cartonsfor the purpose of destroying Ainsect life therein, which consists in creating an electrical discharge across-a gap, interposingl electrical .capacity in series with said gap to distribute the potential drop and limit the current density to avalue below is limited to high tension current, discharging a disruptive conductive current 'across said articles, and controlling the voltage gradient and current densityof the said current across said articles to limit them .to values below the rupturing gradient and carbonizing point respectively, of. said articles.

'il'he process of treating articles for the purpose of destroying insectslife which may v be present therein, which' consists in placing the saidfarticles in a circuit in series with a source of high tension current, discharging 1`05 a disruptive-conductlve current across said `articles, and nterposingmeans in said circuit for. controlling' the 'voltage gradient and current density of the said current be present therein, which consists in plac? ing the said articles in series .with the secondary coil `of a transformer,' discharging a ,disruptive conductive vcurrent`across said articles, and interposing meansv in the circuit for controlling the voltage lgradient and' current density of the said current across said articles to limit them to values below the rupturing gradient and carboniz.

ing points,` respectively, of said articles. 12, The process 'of treating articles for the purpose of destroying insect life'which may be present therein, which vconsists in plac-g.

ing'-the"s aid articles in series witha source of high tension electric-current, discharg-- lng a disruptive conductive current'acrosssaid articles, and interposing 'meansfin the circuit for controlling the voltage gradient and current density of said current across said articles to limit them to values below l the rupturing gradient and carbonizing points, respectively, of said articles.

13. The process of treating articlesvfor the rent in said gap and. subjecting the articles to the said discharges.

14. T he process of treating objects for the*` purpose of destroying insect life, which con sists in creating a -plurality of electrical discharges between different points across a gap, thereby forming a field* of such discharges, interposing electrical capacity in series with said gap, and subjecting the objects vto be treated to the' discharges in said field.-

l15. The process of treating products for the purpose of destroying'insect life which may be present therein, which consists in creating a plurality of independent electrical discharges between different points across a' gap, interposing means 1nV Vseries with said gap to distribute the potential drop and limit vthe current density ofsaid discharges below the voltage gradient ofthe material to be treated, and S'ubjectng the products tou-'the said discharges. .f i f 16. The process of treating products for J the purpose of destroying insect life whichI may be present therein which consists in the cre-ation of a plurality of disruptive conductive currents between a plurality of diferent points across Ika gap, thereby forming a eld of disruptive conductive discharges, and interposing electrical capacity in an electric circuit in series with the said gap -andsubjecting the products to the action of the said' discharges;

17. The process oftreating. articles and.v objects for the purpose of destroying insect life which may be resent therein, which comprises-the crea-tion of'a plurality of independent `disruptive conductive discharges between different points across a gap, thereby forming a field of .such discharges, interpfosing means iny series with said gap for controlling the voltage gradient and curl rent density of the said discharges,and subjecting the objects or articles to be treated to the said discharges. l

. A18. The processofftreating products elec-.`

trically; whichconsists-in placing la plurality of gaps in series in a; circuit, overstressing one of said gaps and thereby causing the discharge ofa disruptive conductive current across sald? overstressed gap and-sub jecting the products to said-current.

In testimony that l claim the foregoing as' -my invention', I have hereunto signed my name this 27th day of April, A. D. 1918.

FRANKLIN s; SMITH. 

